To achieve a noble gas configuration, elements tend to gain, lose, or share electrons to resemble the electron arrangement of the nearest noble gas. Here’s a breakdown for each element:
- Cesium (Cs): Cesium has an atomic number of 55, meaning it has 55 electrons. To attain a noble gas configuration, it needs to lose 1 electron to resemble xenon (Xe), gaining a stable configuration of 54 electrons. Thus, cesium must lose 1 electron.
- Barium (Ba): Barium has an atomic number of 56. It will lose 2 electrons to achieve the stable electron configuration of xenon. Therefore, barium must lose 2 electrons.
- Selenium (Se): Selenium has an atomic number of 34. To reach a stable configuration like krypton (Kr), selenium must gain 2 electrons. Hence, selenium must gain 2 electrons.
- Aluminum (Al): Aluminum has an atomic number of 13. It needs to lose 3 electrons to achieve the configuration of neon (Ne), which is a stable noble gas. Therefore, aluminum must lose 3 electrons.
In summary:
- Cesium: Lose 1 electron
- Barium: Lose 2 electrons
- Selenium: Gain 2 electrons
- Aluminum: Lose 3 electrons